acoustic microscopy

**Acoustic Microscopy** is a **non-destructive inspection technique that uses ultrasound waves to image internal features of packaged ICs** — detecting delaminations, voids, cracks, and foreign materials hidden inside opaque packages without opening them. **What Is Acoustic Microscopy?** - **Principle**: Ultrasonic pulses are sent into the sample. Reflections from internal interfaces (material boundaries) are recorded. - **Medium**: Requires a coupling medium (water) between the transducer and sample. - **Frequency**: 15-300 MHz. Higher frequency = better resolution but less penetration depth. - **Modes**: A-Scan (waveform), B-Scan (cross-section), C-Scan (plan-view image). **Why It Matters** - **Non-Destructive**: Inspects 100% of production without damaging devices. - **Delamination Detection**: The primary tool for finding package delamination (die-to-mold compound, lead frame debonds). - **Incoming Inspection**: Used by OEMs to verify component quality from suppliers. **Acoustic Microscopy** is **ultrasound for electronics** — using sound waves to see inside sealed packages and detect hidden defects.